1. Field of the Invention
The present invention relates to a method, apparatus, computer, and program product for generating a strobe composite image by superposing time-serially obtained object images.
2. Description of the Related Art
An image processing technique for generating and displaying a composite image by extracting only an object portion from a moving image and superposing it on another image is effective to generate a strobe composite image by superposing object images sensed at a plurality of times. In this case, if a user interface that allows the user to superpose a plurality of object images is not available, the user cannot easily generate a strobe composite image, and must spend much time in operations.
Conventionally, a technique for superposing a plurality of image components called layers each having a transparent portion has been used to generate a strobe composite image by superposing a plurality of object images (for example, see reference “Adobe Premier 6.0 Manual, Chapter 7, pp. 281–294”). Initially, only object image regions are extracted from a moving image by an arbitrary method. In this process, a chroma-key method that senses motion of an object in front of a uniform color background, and extracts object images by exploiting color component differences can be adopted. Then, the extracted object image regions are copied to form a plurality of layers using a layer function of image processing software, and a strobe composite image can be obtained by superposing these layers.
However, in order to create a strobe composite image by the conventional technique, the user must manually create layers corresponding to frames, and must manually designate the superposing manner as a hierarchy upon creating layers or must manually adjust the hierarchy of layers after the layers are created. Also, in the conventional technique, the user must execute strobe composition by capturing an image which is to undergo strobe composition, and saving it in a file. For example, if it is impossible to photograph an object in front of a uniform background like in sport games, the chroma-key method cannot be used to extract an object portion from an image. Therefore, a manual extraction process is required, thus taking much time until a strobe composite image is created.
It is often required to shorten the time period required from when an image is obtained until a strobe composite image is created, since the strobe composite image is often used in comments of, e.g., the form of a player in a television live program. Such requirements cannot be met since it takes much time to create a strobe composite image using the conventional technique. Therefore, a method of generating a desired strobe composite image within a short period of time is demanded.